How-To: Fix 98/98 Broken Odometer Worm Gear
#1
08-24-2014, 12:17 PM
How-To: Fix 97/98 Broken Odometer Worm Gear
This article is purely for entertainment purposes only. I, nor F150online.com assume any liability for damages or injuries that may occur if you try to attempt this.
This write-up is intended for the 1997-1998 MY F-150s with the mechanical odometer and trip meter that have stopped rolling, but your speedometer and tachometer still work. If you have a 1999-2003 with the intermittent odometer, click HERE. If your odo/trip meter have stopped working AS WELL AS your speedometer, you've got another issue probably pertaining to the VSS on top of the differential.
Now, it is no surprise to many of us 1997/1998 owners that the odometer and trip meter will eventually fail. This is because the injection-molded plastic Ford used in the late 90s will dry-rot and crumble. This problem affects late 90s Mustangs, F-150s, Rangers, and Explorers. This write-up is geared (pun intended) to fix the 1997 and 1998 MY F-150s only.
Now, the things you will need are:
A new worm gear (available online for $8 on eBay)
7/32 drive socket (disassemble the instrument cluster)
7mm socket (remove the dash)
Let's begin. Using your 7mm socket, remove and disassemble your dash as I have outlined in my cluster color change thread available HERE. Once you've done that, you should have your cluster unplugged and in your hand:
Use the 7/32 and remove the 7x pink screws holding the cluster together.
The lens and bezel will come off. Put them aside (for cleaning) and now we have to remove the actual speedometer from the housing. On the backside, there is a ribbon cable that attaches via a black clamp. Using your fingernails, apply light pressure to each side and pull the clip open so the ribbon cable comes out.
Remove the cluster from the housing and you will see a small drive motor on a clear plastic twist clip. Using your hands or some needle-nose pliars, gently grab and twist CLOCKWISE to remove. You should see the remnants of your old worm gear. Use the needle-nose to remove whats left (tip over the cluster to dump out any pieces that may have fallen in) and then clean off the metal drive wheel.
Insert your new worm gear on and keep applying pressure until there is ~1-2mm gap between the gear and motor. Then, reinstall and twist COUNTER-CLOCKWISE to re-engage with the mileage gear.
Clean off your cluster as you desire, and reassembly is reversal of removal. Put the ribbon cable back in, re-engage the clip to hold it in, apply your lens and put the 7 screws back in, put the 3 power cables back on the cluster and put your dash together. If you did everything correctly, you should be able to enjoy your now-working odometer and trip meter:
This write-up is intended for the 1997-1998 MY F-150s with the mechanical odometer and trip meter that have stopped rolling, but your speedometer and tachometer still work. If you have a 1999-2003 with the intermittent odometer, click HERE. If your odo/trip meter have stopped working AS WELL AS your speedometer, you've got another issue probably pertaining to the VSS on top of the differential.
Now, it is no surprise to many of us 1997/1998 owners that the odometer and trip meter will eventually fail. This is because the injection-molded plastic Ford used in the late 90s will dry-rot and crumble. This problem affects late 90s Mustangs, F-150s, Rangers, and Explorers. This write-up is geared (pun intended) to fix the 1997 and 1998 MY F-150s only.
Now, the things you will need are:
A new worm gear (available online for $8 on eBay)
7/32 drive socket (disassemble the instrument cluster)
7mm socket (remove the dash)
Let's begin. Using your 7mm socket, remove and disassemble your dash as I have outlined in my cluster color change thread available HERE. Once you've done that, you should have your cluster unplugged and in your hand:
Use the 7/32 and remove the 7x pink screws holding the cluster together.
The lens and bezel will come off. Put them aside (for cleaning) and now we have to remove the actual speedometer from the housing. On the backside, there is a ribbon cable that attaches via a black clamp. Using your fingernails, apply light pressure to each side and pull the clip open so the ribbon cable comes out.
Remove the cluster from the housing and you will see a small drive motor on a clear plastic twist clip. Using your hands or some needle-nose pliars, gently grab and twist CLOCKWISE to remove. You should see the remnants of your old worm gear. Use the needle-nose to remove whats left (tip over the cluster to dump out any pieces that may have fallen in) and then clean off the metal drive wheel.
Insert your new worm gear on and keep applying pressure until there is ~1-2mm gap between the gear and motor. Then, reinstall and twist COUNTER-CLOCKWISE to re-engage with the mileage gear.
Clean off your cluster as you desire, and reassembly is reversal of removal. Put the ribbon cable back in, re-engage the clip to hold it in, apply your lens and put the 7 screws back in, put the 3 power cables back on the cluster and put your dash together. If you did everything correctly, you should be able to enjoy your now-working odometer and trip meter:
Last edited by Raptor05121; 10-14-2014 at 05:35 PM.